Block-based video encoding techniques are inherently lossy as they rely on quality compromises in ways that are intended to be minimally perceptible. One such compromise comes in the form of the quantization parameter (QP), which controls the degree of quantization during encoding and thus controls the degree of spatial detail retained from the original video source. As QP increases, spatial detail is increasingly aggregated, which has the effect of lowering the bit rate at the expense of an increase in distortion and loss of quality. Rate control is frequently employed in video encoding or transcoding applications in an attempt to ensure that picture data being encoded meets various constraints, such as network bandwidth limitations, storage limitations, or processing bandwidth limitations, which may dynamically change. These constraints are reflected in the target bit rate for the resulting encoded video stream, and thus the goal of rate control is to maintain the bit rate of the encoded stream within a certain range of the target bit rate, which may remain relatively constant, as found in constant bit rate (CBR) applications, or may vary as found in variable bit rate (VBR) applications. Rate control achieves this target bit rate through manipulation of QP.